add avg script for parsing timings in *.txt

avg.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+if [ $# -gt 0 ]; then
+    pat=$1
+else
+    pat="gather"
+fi
+
+echo PATTERN=$pat
+
+for f in *.txt; do
+    echo -n "$f "
+    grep "$pat" "$f" | \
+        awk -F: '{ total += $2; count++ } END { print total / count }'
+done